ASM International (Finland)

Abstract The sources of non‐uniformity in thin films produced using atomic layer deposition (ALD) have been investigated by reviewing the mechanical hardware of ALD reactors, precursors, and the by‐products of surface reactions. The most common causes of non‐uniformity are overlapping pulses, thermal self‐decomposition of precursors, and non‐uniform gas distribution. Less studied, however, are the consequences of downstream surface reactions of gaseous by‐products. In particular, titanium nitride films have been found to be significantly less uniform than those of transition metal oxides deposited from metal halides. The influence of reaction by‐products on the TiN film growth has been studied by comparing the deposition in the cross‐flow and showerhead style reactors. Finally, the sources of non‐uniformity in plasma enhanced (PE) ALD are illustrated by studying the TiN deposition process.

Abstract. Empirical evidence demonstrates that lakes and reservoirs are warming across the globe. Consequently, there is an increased need to project future changes in lake thermal structure and resulting changes in lake biogeochemistry in order to plan for the likely impacts. Previous studies of the impacts of climate change on lakes have often relied on a single model forced with limited scenario-driven projections of future climate for a relatively small number of lakes. As a result, our understanding of the effects of climate change on lakes is fragmentary, based on scattered studies using different data sources and modelling protocols, and mainly focused on individual lakes or lake regions. This has precluded identification of the main impacts of climate change on lakes at global and regional scales and has likely contributed to the lack of lake water quality considerations in policy-relevant documents, such as the Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC). Here, we describe a simulation protocol developed by the Lake Sector of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) for simulating climate change impacts on lakes using an ensemble of lake models and climate change scenarios for ISIMIP phases 2 and 3. The protocol prescribes lake simulations driven by climate forcing from gridded observations and different Earth system models under various representative greenhouse gas concentration pathways (RCPs), all consistently bias-corrected on a 0.5∘ × 0.5∘ global grid. In ISIMIP phase 2, 11 lake models were forced with these data to project the thermal structure of 62 well-studied lakes where data were available for calibration under historical conditions, and using uncalibrated models for 17 500 lakes defined for all global grid cells containing lakes. In ISIMIP phase 3, this approach was expanded to consider more lakes, more models, and more processes. The ISIMIP Lake Sector is the largest international effort to project future water temperature, thermal structure, and ice phenology of lakes at local and global scales and paves the way for future simulations of the impacts of climate change on water quality and biogeochemistry in lakes.

Atomic layer deposition (ALD) of silicon nitride (SiNx) is deemed essential for a variety of applications in nanoelectronics, such as gate spacer layers in transistors. In this work an ALD process using bis(tert-butylamino)silane (BTBAS) and N2 plasma was developed and studied. The process exhibited a wide temperature window starting from room temperature up to 500 °C. The material properties and wet-etch rates were investigated as a function of plasma exposure time, plasma pressure, and substrate table temperature. Table temperatures of 300-500 °C yielded a high material quality and a composition close to Si3N4 was obtained at 500 °C (N/Si=1.4±0.1, mass density=2.9±0.1 g/cm3, refractive index=1.96±0.03). Low wet-etch rates of ∼1 nm/min were obtained for films deposited at table temperatures of 400 °C and higher, similar to that achieved in the literature using low-pressure chemical vapor deposition of SiNx at >700 °C. For novel applications requiring significantly lower temperatures, the temperature window from room temperature to 200 °C can be a solution, where relatively high material quality was obtained when operating at low plasma pressures or long plasma exposure times.

This article explores the history of atomic layer deposition(ALD) and its relationship with the American Vacuum Society (AVS). The authors describe the origin and history of ALD science in the 1960s and 1970s. They also report on how the science and technology of ALD progressed through the 1990s and 2000s and continues today. This article focuses on how ALD developed within the AVS and continues to evolve through interactions made possible by the AVS, in particular, the annual International AVS ALD Conference. This conference benefits students, academics, researchers, and industry practitioners alike who seek to understand the fundamentals of self-limiting, alternating binary surface reactions, and how they can be applied to form functional (and sometimes profitable) thin filmmaterials. The flexible structure of the AVS allowed the AVS to quickly organize the ALD community and create a primary conference home. Many new research areas have grown out of the original concepts of “Atomic Layer Epitaxy” and“Molecular Layering,” and some of them are described in this article. The people and research in the ALD field continue to evolve, and the AVS ALDConference is a primary example of how the AVS can help a field expand and flourish.

To keep Moore's law alive, 2D materials are considered as a replacement for Si in advanced nodes due to their atomic thickness, which offers superior performance at nm dimensions. In addition, 2D materials are natural candidates for monolithic integration which opens the door for density scaling along the 3rddimension at reasonable cost. This paper highlights the obstacles and paths to a scaled 2D CMOS solution. The baseline requirements to challenge the advanced Si nodes are defined both with a physical compact model and TCAD analysis, which allows us to identify the most promising 2D material and device design. For different key challenges, possible integrated solutions are benchmarked and discussed. Finally we report on the learning from our first lab to fab vehicle designed to bridge the lab and IMEC's 300mm pilot line.

We determined relative nitrate‐nitrogen (NO 3 ‐N) loss rates in 100 north‐mid‐European lakes from late spring to summer by using the exponential function N 2 = N 1 e −k(t 2 −t 2 ), where N 1 and N 2 are NO 3 ‐N concentrations at the beginning (t 1 ) and the end (t 2 ) of the time interval, respectively, and k is the specific NO 3 ‐N loss rate. We found that k decreased with increasing lake depth. Adjusting k to the lake depth (k adj ), we observed that k adj was positively related to spring NO 3 ‐N concentrations, but this relationship became insignificant at mean lake depths exceeding 12.5 m. A relationship between k adj and spring NO 3 ‐N concentrations in lakes shallower than 12.5 m implies that changes in spring NO 3 ‐N concentrations influence the NO 3 ‐N loss rate and thereby summer NO 3 ‐N concentrations. Time series from one Estonian, one German, and 14 Swedish lakes shallower than 12.5 m since 1988 revealed that May to August NO 3 ‐N concentrations have decreased over time everywhere, and the number of time periods exhibiting a NO 3 ‐N depleted condition, i.e., NO 3 ‐N levels below 10 mg L −1 , in these lakes has tripled since 1988. We explained the decreasing NO 3 ‐N concentrations by a reduction in external nitrogen loading including atmospheric deposition, and by changes in climate. The observed prolongation of NO 3 ‐N depleted conditions might be one possible explanation for the increasing occurrence of nitrogen‐fixing cyanobacteria in a variety of lake ecosystems.

Abstract Winter is a long period of the annual cycle of many lakes in the northern hemisphere. Low irradiance, ice, and snow cover cause poor light penetration into the water column of these lakes. Therefore, in northern lakes, respiration often exceeds primary production leading to low dissolved oxygen concentrations. This study aimed to quantify under‐ice metabolic processes during winter in an arid zone lake with little snow cover. This study was carried out in a mid‐latitude lake in Inner Mongolia, northern China. The study lake receives relatively high incoming solar radiation on the ice in mid‐winter, and radiation can penetrate down to the bottom sediment as the lake is shallow and the ice lacks snow cover. Primary production and respiration were estimated during two winters using high‐frequency sensor measurements of dissolved oxygen. To quantify under‐ice metabolic processes, sensors were deployed to different depths. During both winters, sensors collected data every 10 min over several weeks. The amount of solar radiation controlled photosynthesis under ice; temperature and photosynthesis together appeared to control respiration. The balance between gross primary production and ecosystem respiration was especially sensitive to changes in snow cover, and the balance between P and R decreased. Our data suggest that photosynthesis by plankton, submerged plants, and epiphytic algae may continue over winter in shallow lakes in mid‐latitudes when there is no snow cover on the ice, as may occur in arid climates. The continuation of photosynthesis under ice buffers against dissolved oxygen depletion and prevents consequent harmful ecosystem effects.

Minimizing power consumption in multi-processor systems requires the use of multiple supplies with a wide range of regulated voltages and currents. Since one inductor per DC-DC converter is expensive, there is an increasing interest in single-inductor-multiple-output (SIMO) DC-DC converters. Recent research results report a SIMO boost converter and various boost or buck converters with two outputs. This 0.5mum CMOS system is a four- output, single-inductor buck converter with independent regulation of each output.

Adsorptive separation of acetylene (C 2 H 2 ) from carbon dioxide (CO 2 ) offers a promising approach to purify C 2 H 2 with low-energy footprints. However, the development of ideal adsorbents with simultaneous high C 2 H 2 adsorption and selectivity remains a great challenge due to their very small molecular sizes and physical properties. Herein, we report a lithium(I)-chelation strategy for pore space partition (PSP) in a microporous MOF (Li + @NOTT-101-(COOH) 2 ) to achieve simultaneous high C 2 H 2 uptake and selectivity. The chelation model of Li + ions within the framework was visually identified by single-crystal X-ray diffraction studies. The immobilized Li + ions were found to have two functions: (1) partitioning large pore cages into smaller ones while maintaining high surface area and (2) providing specific binding sites to selectively take up C 2 H 2 over CO 2 . The resulting Li + @NOTT-101-(COOH) 2 exhibits a rare combination of a simultaneous high C 2 H 2 capture capacity (205 cm 3 g –1 ) and C 2 H 2 /CO 2 selectivity (13) at ambient conditions, far surpassing that of NOTT-101-(COOH) 2 (148 cm 3 g –1 and 3.8, respectively) and most top-tier materials reported. Theoretical calculations and gas-loaded SCXRD studies reveal that the chelated Li + ions combined with the segmented small cages can selectively bind with a large amount of C 2 H 2 through the unique π-complexation, accounting for the improved C 2 H 2 uptake and selectivity. Breakthrough experiments validated its excellent separation capacity for actual C 2 H 2 /CO 2 mixtures, providing one of the highest C 2 H 2 productivities of 118.9 L kg –1 (>99.5% purity) in a single adsorption–desorption cycle.

Abstract Interaction of under‐ice physical, chemical, and biological processes with lake ice/snow cover is examined to better understand how changing winter climate may affect lake ecosystems. We derived under‐ice dissolved oxygen (DO) dynamics from high‐frequency observations and modified a widely used lake metabolism model by including the effect of freezing and thawing on DO concentration. Estimates were produced for the production and respiration in a shallow lake on the Mongolian Plateau in three winters. Diel, synoptic, and seasonal variations in DO concentration were detected as responses to solar radiation, episodic snowfall events, and occasional convective mixing. Based on the observations and a radiative transfer model, incident solar radiation was partitioned into reflectance, absorbance, and transmittance by the snow and ice cover. For bare ice, the contributions of these three parts were 35%, 39%, and 26%, respectively, while under a new 4.5 cm thick snow cover, the corresponding values were 79%, 17%, and 3%. This points out the critical role of snow and ice on under‐ice light conditions, which is the primary forcing for the temperature and the rate of photosynthesis under ice. The results showed three principal factors, which influenced under‐ice DO and metabolism: (1) thickness and optical properties of ice and snow, which affected the light transfer and depth of the euphotic zone, (2) mediated radiation and ice‐water heat transfer which controlled water temperature, and (3) DO exclusion during freezing and dilution by melt water. This study highlights the ecosystem characteristics in shallow ice‐covered lakes in arid temperate regions and promotes our understanding of the response of the cold aquatic environment to climate change.

The factors controlling pelagic primary and bacterial production of a humic, boreal lake in winter were investigated, combining laboratory and field experiments where some of the predicted consequences of the climate change, i.e.the increased load of phosphate-phosphorus and dissolved organic matter (DOM), were simulated. In situ incubations were performed in eight acrylic tubes lowered underneath the ice cover for 1–4 months. In the lake, production of phytoplankton (0.03–0.33 μg C l −1 day −1 ) was lower than that of bacteria (0.2–2.3 μg C l −1 day −1 ) from the end of January to mid-April. Later in spring, the light conditions improved due to the disappearance of snow and finally ice itself, and primary production was revived. The importance of light as the factor controlling primary production in winter was confirmed in laboratory experiments where additions of phosphorus and DOM did not enhance the primary production. These same enrichments resulted in higher growth rates and production of bacteria. However, bacterioplankton was simultaneously controlled by heterotrophic flagellates, as in the laboratory experiments the exclusion of flagellates always resulted in higher yields of bacteria of increased cell size. There was also some evidence that the quality of substrates is of importance for microbial activities. The importance of temperature was highlighted with the significant correlation ( r2 = 0.59) between bacterial production and temperature within the range 0.6–2.1°C. Thus, on the boreal zone the possible warming of climate may lead to enhanced activities in winter, but under unchanged light conditions no effects on primary production will be expected.

We show how interfacial oxide engineering in La-doped hafnium zirconate (HZO) ferroelectric (FE) capacitor stacks can be used to significantly improve the ferroelectric response and remnant polarization (PR) of the HZO. This is achieved by incorporating either a 1 nm TiO2seed and/or 2 nm Nb2O5cap layer in a bilayer (BL) and/or trilayer (TL) configuration with TiN top and bottom electrodes. We show how the Nb2O5cap is able to facilitate the transition from (anti-FE) tetragonal into (FE) orthorhombic phase by injecting oxygen in the HZO and find that the TiO2seed layer favorably improves the grain orientation inside the HZO, resulting in a higher 2PRand reduced wake-up. Finally, depending on the precursors of Hf and Zr that are used, we demonstrate both trilayer devices with an endurance of up to 1011cycles with a final 2PRof ~30μC/cm2at 1.8 MV/cm or devices with a record high 2PR,maxof 66.5 μ C/cm2after 3× 106cycles at 3 MV/cm.

Titanium nitride (TiN) films were deposited using plasma-enhanced atomic layer deposition (PEALD) from the organometallic precursor tetrakis-dimethyl-amino-titanium (TDMAT) with hydrogen () as a coreactant. Low-resistivity values lying from 210 to were achieved for 10 nm thick films deposited at low temperature: . The effects of temperature, plasma time, and plasma power were investigated. It was demonstrated that the chemical reaction is complementary and self-limiting. A minimum energy is necessary to reach the low-resistivity plateau. Chemical and physical properties of the films are also reported and a surface reaction mechanism is proposed. It is suggested that after TDMAT chemisorption to the surface, amines are removed by hydrogen radicals, and at the same time, titanium carbide bonds (Ti–C) are formed. The low resistivity results from the presence of or phases in the PEALD TiN film. The industrial viability of this process was also evaluated on 300 mm wafers. Good performances were obtained on wafer-to-wafer uniformity and step coverage, while some improvements related to the within-wafer uniformity are required.

Length-biomass regressions were established for the cladoceran Bosmina longispina maritima and for the copepods Euryremora affinis hirundoides and Limnocalanus macrurus , all common in the Baltic Sea. Biomass was analysed as individual organic carbon content. For Bosmina , length was a weak estimator of biomass; only 51% of the variation in carbon content was explained by length. For pre-adult stages of copepods length was a rather good estimator of biomass. For Euryremora nauplii. the length-carbon relationship was best described by linear equations (r 2 was between 0.49 and 0.69), and for copepodite stages (CI-V) by exponential functions (r 2 = 0.81). The regressions for two different sampling areas (Baltic proper and Bothnian Bay) did not show statistically significant differences. Among the copepodites (CI-V) of Limnocalanus there was a linear relationship between length and carbon content (r 2 = 0.76). In both copepod species there was no or a weak correlation between length and biomass among adults.

) nanodomains, utilizes both transition metals and oxygen redox to yield substantial energy density. However, the inherent heterogeneous nature and distinct nanodomain redox chemistries of layered lithium-rich oxides will inevitably cause pernicious lattice strain and structural displacement, which can hardly be eliminated by conventional doping or coating strategies and result in accelerated performance decay. Herein, we incorporate a strain-inhibiting perovskite phase coherently grown within the layered structure to effectively restrain the displacement and lattice strain during uneven Li-ion extraction. The enhanced mechanochemical stability of the designed cathode benefits the persistent structure and reversible oxygen redox, thereby achieving high initial Coulombic efficiency and stable cycling and voltage profiles. Our approach of lattice engineering alleviates the strain and displacement caused by inhomogeneous reactivity between heterogeneous nanodomains and promotes the development of advanced cathode materials with long durability.

1. Although the intrinsic habitat preferences of a species can be considered to be fixed, the realized habitat use depends on the prevailing abiotic and biotic conditions. Often the core habitats are occupied by dense and stable populations, while marginal habitats become occupied only at times of high density. In a community of interacting species, habitat uses of different species become inter-related, for example an increased density of a strong competitor forcing a weaker competitor to use more marginal habitats. 2. We studied the spatio-temporal distribution patterns of three common small mammal species, the bank vole Myodes glareolus; the field vole Microtus agrestis; and the common shrew Sorex araneus, in a 4-year trapping study carried out on six large islands, each containing a mixture of three main habitat types (forest, field and clear-cut). We experimentally released least weasels (Mustela n. nivalis) to some of the islands to see how the focal species respond to increased predation pressure. 3. Both vole species were largely restricted to their core habitats (bank voles to forests and field voles to fields) at times of low population density. With increasing density, the relative habitat use of both species increased in the clear-cut areas. The common shrew was a generalist in its habitat use at all population densities. 4. The release of the weasels changed the habitat use of all study species. 5. The vole species showed a stronger aggregated pattern than the common shrew, especially at low population density. The vole aggregations remained in the same localities between seasons, except in the case of bank voles after the weasels were released. 6. Bank voles and field voles avoided each other at high density. 7. We conclude that intrinsically differential habitat requirements and flexibility to modify habitat use facilitate the coexistence of the two competing vole species in mosaic landscapes consisting of boreal forests and open habitats.

Abstract Analyses of carbon stable isotopes are often used to estimate the contributions of allochthonous and autochthonous dietary resources to aquatic consumers. Most pelagic food web studies assume that all phytoplankton taxa have a similar δ 13 C value. We studied pelagic food web compartments (dissolved inorganic carbon [ DIC ], phytoplankton, bacteria, seston, cladoceran zooplankton) in 12 small (< 0.1 km 2 ) lakes in southern Finland. These lakes were classified as oligotrophic, mesotrophic, eutrophic, and dystrophic based on their concentrations of total phosphorus and dissolved organic carbon. Additionally, we studied phytoplankton photosynthetic carbon fractionation (ε p ) in laboratory conditions. The photosynthetic fractionation in 28 phytoplankton cultures from nine different phytoplankton classes varied significantly at the class level, and fractionation correlated significantly with the DIC concentration of the growth media. In small boreal lakes, the δ 13 C values of different phytoplankton taxa, as directly measured or estimated from the δ 13 C values of biomarker fatty acids, varied greatly (−18‰ to −44.5‰). Phytoplankton δ 13 C values varied significantly by lake type and were most depleted in dystrophic lakes even though the δ 13 C values of the DIC was similar to mesotrophic lakes. Further within‐taxa variation was found between lakes and between different depths within a lake. Vertical samples from dystrophic lakes also showed lower ε p in the phytoplankton from meta‐ and hypolimnion, possibly as a result of reduced light intensity. Altogether, in nine of the 10 sampled lakes, the δ 13 C values of cladoceran zooplankton were between the minimum and the maximum phytoplankton δ 13 C value of each lake, and thus, phytoplankton alone could explain zooplankton δ 13 C values. We conclude that stable isotope mixing models should take into account carbon variation among different phytoplankton taxa.

The diversity of covalent organic frameworks (COFs) is continuously expanding, providing various materials with tailor-made structures and properties. However, the development of crystalline three-dimensional (3D) COFs with new topologies is an essential but arduous challenge. In this study, we first developed one kind of 3D COFs with the lil topological structure, which were assembled by D 4h - and C 2h -symmetric building blocks. The 3D COFs were determined in a space group of Imma, in which each D 4h -symmetric unit is connected with four C 2h -symmetric units, forming a noninterpenetrated network. The densely packed copper phthalocyanine and stable polyimide linkage render these COFs as a polymeric material with high dielectric constant and low dielectric loss at high frequencies (>1 kHz). Significantly, the dielectric constant was determined as high as 63, which constitutes a new record value among phthalocyanine-based and polyimide polymers. Therefore, this study not only provides important guidance for the design of 3D lil -net COFs but also supplies promising materials for application in high-energy-density and pulsed capacitors.

is a unique industrially compatible two-in-one physisorbent that serves as a multipurpose molecular separator by virtue of reversible flexibility with outstanding separation performances.

Developing propane-selective adsorbents for propane/propene (C 3 H 8 /C 3 H 6 ) separation can energy-efficiently produce high-purity C 3 H 6, but it remains unexploited in porous hydrogen-bonded organic frameworks (HOFs) because of lacking effective C 3 H 8 binding sites. Reticular chemistry provides a powerful strategy for fine-tuning of pore size and functionality; however, this strategy is extremely challenging to be implemented in HOFs owing to the weak H-bonds with poor directionality. Herein, we report, for the first time, the implementation of a reticular chemistry strategy to design and synthesize a series of isoreticular HOFs (ZJU-HOF-59–ZJU-HOF-62) for achieving highly efficient C 3 H 8 /C 3 H 6 separation. Four isoreticular HOFs were constructed by four tetracarboxylic ligands, in which their pore sizes and functional sites are systematically engineered. These HOFs exhibit a tunable and gradually improved binding preference of C 3 H 8 over C 3 H 6 . Among them, ZJU-HOF-62 with abundant dialkynyl sites and suitable pore sizes demonstrates the fully inverse C 3 H 8 /C 3 H 6 separation, exhibiting the highest C 3 H 8 uptake (146.8 cm 3 g –1 ) and C 3 H 8 /C 3 H 6 selectivity (1.53) at 298 K and 1 bar. Theoretical calculations reveal that multiple dialkynyl and carboxylic sites provide stronger multipoint H-bonding and van der Waals interactions with C 3 H 8 than C 3 H 6 . The excellent separation capacity of ZJU-HOF-62 for actual C 3 H 8 /C 3 H 6 mixtures was proved by dynamic breakthrough experiments, providing a maximum C 3 H 6 productivity of 12.1 L kg –1 . This work opens the design of porous HOFs for challenging C 3 H 8 /C 3 H 6 separation.